Apparatus of this type is known from U.S. Pat. No. 5,111,645, WO86/01972, EP 241276, WO88/04885 and WO88/05626 each of which the use of a toothed stripper drum to strip the portions to be harvested from the plants, the stripped material being fed to a conveying auger. These earlier disclosures all contain examples which suggest that the drum can feed the material directly to the auger or to a belt conveyor which in turn feeds the auger. In practice the former arrangement has not been found to be viable, however, and it is now conventional to interpose a belt conveyor between the stripper drum and the auger. In U.S. Pat. No. 5,11,645, for example, there are other proposals, such as the use of a smaller vaned rotor behind the stripper drum, the vanes of which are intended to impel separated crop parts rearwards.
While it is usually the aim to leave the plant stems on the ground and take only the crop being stripped, this is not always possible. If cereal plants have been laid by wind and rain, for example, it is found that a considerable part of the stalks is taken in by the stripper as well as the grain separated from the stalks.
That would not be a problem if the stalks can be passed safely through the harvesting apparatus but experiments have indicated that conventional crop strippers are able to cope with these conditions only by providing a belt conveyer between the stripping drum and the auger which transmits the stripped crop onwards for collection. Attempts to produce a more compact grain stripper by omitting the belt conveyer show that such an apparatus cannot cope when a significant part of a cereal crop has been laid flat.
This is partly because the grain gathered from a laid crop follows a different trajectory and tends to be spilt from the back of the stripper drum. Also, it is found that the weakened stalks can become trapped between the drum and the auger, hanging on the crop-collecting pan under the auger, where they block the free passage of the stripped crop through the auger. Eventually, this material, together with some of the crop is redeposited on the ground, and as a result there can be a significant loss of crop.
It is an object of the present invention to provide a new form of stripper apparatus that is capable of handling crops such as laid cereal crops with less risk of disturbance by stalks or stems drawn into the apparatus.